In noisy environments speech recognition systems can be susceptible to errors due to the pickup of extraneous noise. A particular problem in speech recognition systems is the false detection of background noise as speech that introduces errors and interrupts the flow of the dialog by introducing “dead air” where the system and the user are both waiting for the other to speak. Such a problem significantly inhibits the usability and user experience.
Interactive voice response (IVR) systems, for example, adopt a different style where the system and user take turns interacting based on system prompts and user responses. However problems can occur in noisy environments for this type of system, as well. Since the only channel for the system to communicate to the user is via audio, it is possible that the system reacts (“hears”) to a noise interruption and stops playing a prompt that instructs the user what to do next. When the user has not actually spoken and the IVR prompt was interrupted by the extraneous noise, the resulting “dead air” silence of the IVR system is confusing. One limited solution to this problem offered by IVR systems is the use of DTMF (dual-tone multi-frequency) data entry. This can be more robust than speech recognition based systems; however, these systems typically suffer from poor user interfaces because of the limited number of choices possible for each answer.